Removable cover for current limiting fuse housing



Nov. 14, 1961 w. M. SCOTT, JR 3,009,039

REMOVABLE COVER FOR CURRENT LIMITING FUSE HOUSING Filed May 19, 1959 2Sheets-Sheet 1 Ia? 5; E z 5- 5.

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Mil/AM M..Sc07'7; J42.

Nov. 14, 1961 w. M. SCOTT, JR 3,009,039

REMOVABLE COVER FOR CURRENT LIMITING FUSE HOUSING Filed May 19, 1959 2Sheets-Sheet 2 Z 58 W 2 J7 J2 f m 76 -w 7:

Z I G 4- J8 J7 62 J6 United States Patent O 3, 0 REMOVABLE COVER FORCURRENT LIMITING FUSE HOUSING William M. Scott, Jr., Bryn Mawr, Pa.,assignor to I-T-E Circuit Breaker Company, Philadelphia, Pa., acorporation of Pennsylvania Filed May 19, 1959, Ser. No. 814,214 7Claims. (Cl. 200-133) My invention relates to a means for locking andremoving a current limiting fuse housing from its associated breakerwhere considerable force is required to separate the disconnect contactsconnecting the two units.

Current limiting fuse housings associated with circuit breakers Wherethe current limiting fuses are electrically and mechanically coordinatedwith the circuit breakers are set forth in copending application SerialNo. 622,042, filed November 14, 1956, now Patent No. 2,924,688, entitledEnd Mounting of a Current Limiting Device Associated With a CircuitBreaker, in the name of William Harold Edmunds and assigned to theassignee of the present invention.

Since there must be high pressure contact engagement between thedisconnects which electrically connect the current limiting fusespositioned within a housing and the circuit breaker disconnects, a largemechanical force is required to remove the fuse housing from. thecircuit breaker.

In the past, the operator could grip only the relatively smooth sides ofthe fuse housing, or a relatively short protruding lip of the fusehousing when removing the fuse housing.

In accordance with my invention, I provide a bale or wire means which isconnected to a plate fastened to the fuse housing. A rigid connectingmeans extending from the base extension of the circuit breaker whichreceives the fuse housing is then taken through a key-type opening inthe plate so that the plate and thus the housing is locked or unlockedto the circuit breaker depending on the position of the key-typeopening. When the plate is in a looked position, the fuse housing isrigidly secured to the circuit breaker base. Movement of the plate inthis position is normally prevented by a bale which is pivotally mountedto the plate and can interfere with movement of the plate. When the fusehousing is to be removed, the bale is lifted from its interferingposition to permit the plate to be moved from a locked position to anunlocked position by movement of the keyed connection between thecircuit breaker base and the fuse housing. However, the plate is stillattached to the fuse housing and may be pulled upwardly by means of thebale which previously operated as an interfering means, so that the baleplate and fuse housing are lifted as a unit. The bale, therefore, servesthe dual function of being a handle for removing the fuse housing fromthe circuit breaker, as well as means for rigidly holding the plate andthus, the fuse housing, locked to the circuit breaker base.

Accordingly, a primary object of my invention is to provide a novelmanner for locking and removing a fuse housing from a circuit breaker.

Another object of my invention is to provide a novel grasping means foreasily removing a fuse housing from a circuit breaker wherein thegrasping means further operates as a looking means to rigidly secure thefuse housing and the circuit breaker.

Another object of the invention is to provide a simple means for lookinga fuse housing to a circuit breaker housing.

A further object of the invention is to provide an ef- 3,009,039Patented Nov. 14, 1961 fective means for removing a fuse housing from acircuit breaker housing.

Another object of my invention is to removably secure a plate to acurrent limiting fuse housing, and pro. vide a key slot in the platewhich cooperates with fastening means extending from the circuit breakerbase whereby the fuse housing is rigidly locked by a bale fastened tothe plate when the plate is in a first key position, and is capable ofbeing removed by the bale when the bale is moved from its lockingposition and the plate is in a second key position. 7

These and other objects of my invention will become apparent from thefollowing description when taken in connection with the drawings, inwhich:

FIGURE 1 is an exploded perspective view ofa cir-' cuit breaker housinghaving a removably connected fuse housing wherein the fuse housing ismodified in accord ance with the present invention.

FIGURE 2 is a cross-sectional detail view of the manner in which theplate of FIGURE 1 is movably secured with respect to the fuse housing.

FIGURE 3 is a top view of the fuse housing of FIG URE 1 with the baleand plate in the locked positions.

FIGURE 4 is a top view similar to FIGURE 3 wherein the bale has beenlifted from its interfering position, and the plate moved to an unlockedposition so that the bale may be used to pull the fuse housing out ofengagement with the circuit breaker housing.

Referring now to FIGURE 1, the figure shows a structure which, for theexception of the fuse housing cover structure, is fully described in theabove noted copending application Serial No. 622,042.

In FIGURE 1, a circuit breaker housing 20 is provided with an extendingbase portion 21 which may be either an integral part of the circuitbreaker 20 or may be a removable base portion. An operating mechanism ofany desired type is contained within circuit breaker housing 20, such asthe mechanism shown in US. Patent No. 2,574,093 to William HaroldEdmunds. Operating handle 30 operates a pair of contacts for each phase(not shown) of the three-phase circuit breaker illustrated in FIGURE 1.Contacts of each of the circuit breaker phases are terminated bydisconnect contacts 31, 32 and a contact 33 which is not seen in FIGURE1.

The extension 21 of FIGURE 1 carries additional disconnect contacts 34,35 and 36 which cooperate with contacts 3-1, 3-2 and 33 respectively forconnecting a current limiting fuse in series with each of the respectivecircuit breaker phases. Each of disconnect contacts 31 through 36 are ofthe tulip-clip type, described in copending application Serial No.536,586, filed September 26, 1955, and assigned to the assignee of thepresent invention, and receive a stud means in electrical and mechanicalengagement. However, for purposes of the present invention, disconnectcontacts 31 through 36 could be of any desired type.

Fuses, such as fuse 40 of FIGURE 1, are provided for each phase ofcircuit breaker 20, and have disconnect studs, such as disconnect studs41. through 45 whe'r'es'tuds 4-1, 42 are associated with fuse 40'; studs43 and 44 are associated with a fuse of the middle phase, and stud 45and a stud not shown are associated with the fuse of the third phase.Studs 41 and 42; cooperate with disconnects 36 and the disconnect atlocation 33 in FIGURE 1, while disconnects 43 and 44 cooperate withdisconnects 35 and 32 respectively, and disconnect 45' and a seconddisconnect of the third fuse (not shown) cooperate with disconnects 34and 31 respectively.

Because the connection between the current limiting fuse studs and theircooperating tulip-clip connectors must be a low resistance connection toavoid the generation of excess heat, a substantial mechanical force isprovided for this connection. This, however, makes it very diificult topull the fuse housing away from the circuit breaker housing.

In the present invention, I have solved this problem by providing a balemeans 50, seen in FIGURES 1, 3 and 4, which is pivotally connected toears 52 and 54 of plate 56. Plate 56 is movably secured to the top 57 ofhousing 37 by bolt means 58 and 60 which extend through elongatedopenings 62 and 64 respectively of plate 56, and are secured beneath thetop of housing 37.

A cross-sectional view of this securing structure is shown in FIGURE 2for bolt 58. Bolt 58 has a head larger than the width of slot 62 inplate 56, and is secured beneath the top of cover 37 by a lock nut 66.However, the connection is such that there can still be relativelongitudinal motion between plate 56 and top 57 of housing 37.

In order to rigidly secure fuse housing 37 to the extended base 21 ofthe circuit breaker housing 20, the plate 56 is provided with the twokey slots 68 and 70. These key slots cooperate with bolts 72 and 74 ofFIG- URE 1, which have enlarged heads 76 and 78 respectively which canpass through openings 80 and 82 in the top of housing 37, as seen inFIGURE 1, and the enlarged portion of key slots 68 and 70.

Accordingly, when the fuse housing 37 is locked to extended base 21, theplate 56 will be in the position of FIGURE 3 where the enlarged heads 76and 78 of bolts 72 and 74 lie over the reduced width portion of keyslots 68 and 7 0. When the fuse housing 37 is to be unlocked fromextended base 21, the plate 56 is moved from the position of FIGURE 3 tothe right and to the position of FIGURE 4 whereupon enlarged heads 76and 78 of bolts 72 and 74 move into the enlarged key slot portion. Thehousing may now be lifted upwardly with the bolt heads 76 and 78clearing the larger diameter openings to disconnect fuse housing 37 fromhousing 20.

As previously set forth, a substantial amount of force is required tophysically disconnected housing 37. In the present invention, however,the bale 50 may be pivoted upwardly to an operating position, as shownin FIGURE 4, so that bale 50, which may be conveniently grasped,

can be pulled upwardly to exert a force on the fuse housing 37 throughthe plate 56 and securing bolts 58 and 60 which secure the plate to thehousing 37.

-I have further found that the lifting function of bale 50 can becoordinated with the locking and unlocking function of plate 56 in anovel manner whereby bale 50 may interfere with the movement of plate 56so that the plate 56 can be secured in the locked position. Morespecifically, the upper surface 57 of housing 37 is provided with a pairof protrusions 84 and 86, and a further protrusion 88. As shown inFIGURES l, 3 and 4, the protrusions 84 and 86 are spaced to receive aportion of bale 50 between them, while protrusion 88 is positionedadjacent the other side of bale 50 when the bale is in a flat andinterfering position.

The upper surface 57 is further provided with a protrudingpin 90 havinga necked-down portion 92 at an intermediate portion thereof. Thenecked-down portion 92 of pin 90 cooperates with an indentation 94 inbale 50 so that the necked-down portion 92 can lock bale 50 in theinterfering position when receiving indentation 94. When the bale is inthe position of FIGURE 3, it will be readily apparent that the plate 56cannot be moved to the right and to the position of FIGURE 4, since thismotion is prevented by protrusions 84, 86 and 88. Accordingly, the plate56 is secured in its locking position and the fuse housing 37 is lockedto the circuit breaker housing.

When the bale 50 is pressed at its center to remove indentation 94 fromnecked-down portion 92 of pin 90, the bale may be rotated upwardly froman interfering position to the operating position of FIGURES 1 and 4,and

at this point the plate 56 may be moved to the right. Thereafter, thebale may be readily used to remove the fuse housing from the circuitbreaker housing in the manner previously described.

If desired, the plate 56 can be interlocked with the circuit breakertrip mechanism so that movement of plate 56 to the unlocked positionwill trip the circuit breaker. This structure is schematically shown inFIGURE 1 by the dotted line from plate 56 to circuit breaker 20 andprevents the removal of the fuse housing while the circuit breaker isclosed and current flows through the disconnect contacts.

Although I have described preferred embodiments of my novel invention,many variations and modifications will now be obvious to those skilledin the art, and I prefer therefore to be limited not by the specificdisclosure herein but only by the appended claims.

I claim:

1. In a circuit interrupter; said circuit interrupter comprising a firsthousing containing a current limiting fuse and a second housingcontaining a circuit breaker; said current limiting fuse havingdisconnect contact means; said circuit breaker having disconnectedcontact means; said current limiting fuse disconnect contact means beingconnectible to said circuit breaker disconnect contact means; means forremoving said first housing and said current limiting fuse from saidsecond housing and said circuit breaker when said disconnect contactmeans are connected; said removing means comprising a bale; said balebeing pivotally operatively connectetd to the top of said first housing;a plate means; said bale being carried by said plate means; said platemeans being movably secured to the top of said first housing and beingmovable in a plane parallel to the top of said first housing between alocked position and an unlocked position with respect to said secondhousing.

2. In a circuit interrupter; said circuit interrupter comprising a firsthousing containing a current limiting fuse and a second housingcontaining a circuit breaker; said current limiting fuse havingdisconnect contact means; said circuit breaker having disconnect contactmeans; said current limiting fuse disconnect contact means beingconnectible to said circuit breaker disconnect contact means; means forremoving said first housing and said current limiting fuse from saidsecond housing and said circuit breaker when said disconnect contactmeans are connected; said removing means comprising a bale; said balebeing pivotally operatively connected to the top of said first housing;a plate means; said bale being carried by said plate means; said platemeans being movably secured to the top of said first housing and beingmovable between a locked position and an unlocked position with respectto said second housing; said bale being pivotally movable between aninterfering position and an operating position; said bale blockingmovement of said plate means to said unlocked position when said balemeans is in said interfering position and permitting movement of saidplate means to said unlocked position when said bale means is in saidoperating position.

3. In a circuit interrupter; said circuit interrupter comprising a firsthousing containing a current limiting fuse and a second housingcontaining a circuit breaker; said current limiting fuse havingdisconnect contact means; said circuit breaker having disconnect contactmeans; said current limiting fuse disconnect contact means beingconnectible to said circuit breaker disconnect contact means; lockingmeans for locking said first housing to said second housing; saidlocking means comprising a plate; said plate being movably secured tosaid first housing; said second housing having an extension meansprojecting through aperture means in said plate; said plate beingmovable to a locked position and an unlocked position with respect tosaid extension means; said plate when in said locked position having aportion thereof disposed within a recess of said extension means.

4. In a circuit interrupter; said circuit interrupter comprising a firsthousing containing a current limiting fuse and a second housingcontaining a circuit breaker; said current limiting fuse havingdisconnect contact means; said circuit breaker having disconnect contactmeans; said current limiting fuse disconnect contact means beingconnectible to said circuit breaker disconnect contact means; lockingmeans for locking said first housing to said second housing; saidlocking means comprising a plate; said plate being movably secured tosaid first housing; said second housing having an extension means; saidplate being movable to a locked position and an unlocked position withrespect to said extension means; and a handle means; said handle meansbeing connected to said plate for removing said first housing from saidsecond housing; said handle means being movable from an interferingposition to an operating position; said handle means preventing movementof said plate to said unlocked position when said handle means is insaid interfering position.

5. In a circuit interrupting means; a first circuit interrupter securedwithin a first housing and a second circuit interrupter secured within asecond housing; said first and second circuit interrupters havingcooperating disconnect means for connecting said first and secondcircuit interrupters; a plate; said plate being movably mounted to theupper surface of said first housing; said plate having a key slottherein; said second housing having a protruding member secured thereto;said protruding member being positioned Within said key slot of saidplate; said plate being movable between a locking position with saidprotruding member in a restricted portion of said key slot and anunlocked position with said protruding member in an enlarged portion ofsaid key slot; said plate and said first housing being removable fromsaid first housing only when said plate is in said unlocked position.

6. In a circuit interrupting means; a first circuit interrupter securedWithin a first housing and a second circuit interrupter secured within asecond housing; said first and second circuit interrupters havingcooperating disconnect means for connecting said first and secondcircuit interrupters; a plate; said plate being movably mounted to theupper surface of said first housing; said plate having a key slottherein; said second housing having a protruding member secured thereto;said protruding member being positioned within said key slot of saidplate; said plate 'being movable between a locking position with saidprotruding member in a restricted portion of said key slot and anunlocked position with said protruding member in an enlarged portion ofsaid key slot; said plate and said first housing being removable fromsaid first housing only when said plate is in said unlocked position;said plate having a handle secured thereto; said handle being operableto remove said plate and first housing from said second housing whensaid plate is in said unlocked position.

7. In a circuit interrupting means; a first circuit interrupter securedwithin a first housing and a second circuit interrupter secured within asecond housing; said first and second circuit interrupters havingcooperating disconnect means for connecting said first and secondcircuit interrupters; a plate; said plate being movably mounted to theupper surface of said first housing; said plate having a key slottherein; said second housing having a protruding member secured thereto;said protruding member being positioned Within said key slot of saidplate; said plate being movable between a locking position with saidprotruding member in a restricted portion of said key slot and anunlocked position with said protruding memher in an enlarged portion ofsaid key slot; said plate and said first housing being removable fromsaid first housing only when said plate is in said unlocked position;said plate having a handle secured thereto; said handle being operableto remove said plate and first housing from said second housing whensaid plate is in said unlocked position; said handle being movable froman interfering position to an operable position; said handle preventingmovement of said plate to said unlocked position when said handle is insaid interfering position.

References Cited in the file of this patent UNITED STATES PATENTS1,312,626 Grannis Aug. 12, 1919 2,256,232 Bennet Sept. 16, 19412,744,982 Smith May 8, 1956 2,905,791 Edmunds Sept. 22, 1959

